In this project we focus on a difference in perspective between articulatory phonologists, represented in Carol Fowler's project and researchers of reading, represented the other projects. In articulatory phonology, there is no phonological level of representation intermediate between the phonetic gesture and the syllable. However, it has been assumed in research on reading that there is a psychologically real level of linguistic structure between the gesture and the syllable, and that letters of an alphabetic orthography represent that level of structure (traditionally athe segment or phoneme). We confront this theoretical difference directly in research outlined in this project. In the first line of research, we attempt to distinguish a view that letters of an alphabetic writing system map onto a level of phonological representation roughly corresponding to phonological segments (consonants and vowels) from a view that such phonological units do not exist. In particular, we focus on the question whether phonological gestural primitives participate in constellations larger that the single gesture but smaller than the syllable. Next, e explore the categorical nature of primitive units of the spoken language regardless of whether the units are individual gestures or, rather are gestural constellations corresponding to consonantal and vocalic segments. We focus on listener/talkers' classifications of certain perceptibly distinct productions of consonants (or vowels) as members of a common phonological category, and we interpret the classifications as indications that those categories have psychological reality for language users. Evidence comes in part from examinations of "gestural drift: in productions by bilingual speakers. In research to date we have found that phonetic characteristics of stop consonants both in a native language and in an ambient, nonnative, language drift toward that of stop consonants of the ambient language over time. That the drift occurs in stops of both languages suggests that speaker/listeners are detecting correspondences between phonological units in the two languages, and therefore, that the phonological primitives of both languages are categories. To provide converging evidence, we explore patterns of assimilation to native phonological categories of phonological category. In addition, we explore assimulations to a common phonological category of consonants or vowels of different dialects of a language that are perceptibly distinct among speakers of different dialects. In a final section, we ask whether consonantal and vocalic phonological categories are qualitatively distinct kinds of categories, as posited in articulatory phonology(and autosegmental phonologies), and as also suggested by evidence on lateralization of the two kinds of gesture, or by findings of vowel-consonant differences in perception. These findings will have direct relevance to experiments on vowel and consonant identification in reading that we propose in the other projects.